Since this updates ghc, every haskell port needs to be revbumped. In order to
avoid a huge monster commit and due to the number of revbumps required I will
do this as time permits.

This change also renames all ports provided by the platform to hs-$pkgname
instead of hs-platform-$pkgname. We should rather have one well-maintained and
high-quality release rather than two conflicting and hardly interoperable
versions. This change will break all ports that currently depend on
a haskell-platform-$pkgname port.

This change also merges all ports provided by the haskell platform (except for
GHC) into a single Portfile using subports. This should simplify further
updates of the platform.